Degradation products of fluorinated greenhouse gases

A hand holding a glas of waterClick to enlarge
TFA formed as a degradation product of fluorinated greenhouse gases can be
Source: bigfoot /

Fluorinated gases in the atmosphere form degradation products such as trifluoroacetic acid (TFA). TFA enters the water cycle through precipitation and cannot be removed by proportionate means.

Fluorinated gases emit in the atmosphere from production, use and after use phase of refrigeration and air conditioning systems (RAC), foams, and from other applications including solvents, fire extinguishing agents and aerosol propellants, and as anaesthetic gases. In the atmosphere, fluorinated gases form a wide variety of degradation products. The degradation products are transported from the atmosphere via precipitation into the environment. The complete degradation usually leads to hydrofluoric acid (HF) and, for many fluorinated gases, also to persistent, i.e. very stable, trifluoroacetic acid (TFA). At present, there is no method known to remove TFA from the water cycle by proportionate means.

It is expected, that the spectrum of gases currently in use will shift to halogenated substances with lower GWP. However, the change to shorter-lived gases such as R1234yf, R1234ze(E), and R1233zd(E) will lead to continuous and even increasing input of persistent TFA into the environment. The study titled "Type, environmental concentrations, and fate with particular regard to new halogenated substitutes with low global warming potential" commissioned by the German Environment Agency examines degradation products formed by halogenated gases in greater detail.

Only a decisive change towards the use of natural refrigerants - such as hydrocarbons, carbon dioxide, ammonia, air or water - can effectively reduce the input of fluorinated or other halogenated degradation products into the environment.

More information about TFA is available via the links and publications listed.